Braidless guide catheter

ABSTRACT

Guide catheter incorporating a braidless construction having increased performance characteristics for catheterization procedures. The guide catheter may include a tracking wire, inner or outer guide for positioning the guide catheter within the patient&#39;s vascular system.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to guide catheters and diagnosticcatheters used in medical catheterization procedures. In particular, thepresent invention relates to an improved guide or diagnostic catheterhaving a simple, braid-free catheter design, which is capable ofperforming the functions of conventional diagnostic and guide catheters.

[0003] 2. Description of the Prior Art

[0004] Guide catheters and diagnostic catheters are well known for usein coronary catheterization and percutaneous transluminal coronaryangioplasty (PTCA) procedures. Guide catheters aid in treatment ofarterial lesions by providing a conduit for positioning dilatationballoon systems across an arterial stenosis. Guide catheters anddiagnostic catheters work with various assemblies for performing othermedical, therapeutic, and diagnostic procedures, such as dye delivery,arterial flushing, or arterial pressure monitoring.

[0005] Diagnostic catheters are used during cardiac catheterization fordiagnosis of coronary artery disease in order to define vessel anatomy,isolate lesions, and identify adjacent cardiac branches which mayimpinge on the lesion and affect ventricular function.

[0006] For diagnosis of the coronary artery, the femoral artery isentered percutaneously and a sheath is inserted into the artery toprovide access to the patient's vascular system. The diagnostic catheteris inserted into the femoral artery through this introducer sheath overa guide wire and advanced up the aorta to the aortic arch. Once over theaortic arch, the guide wire may be removed. A Y-adapter and manifoldassembly are attached to the diagnostic catheter for implementation ofdiagnostic procedures, such as dye delivery, flushing capabilities, andarterial pressure monitoring.

[0007] The diagnostic catheter design generally includes a shaft havinga proximal and a distal end. A lumen extends longitudinally through theshaft from the proximal to the distal end. Operably connected to theproximal end of the shaft is a hub assembly, for connection tocatheterization equipment, and connected to the distal end of the shaftis a soft tip.

[0008] The distal end of the guide catheter shaft is shaped to accessthe ostium of the coronary artery having the stenotic lesion. Differentshapes may be employed for access to the ostium of a right or leftcoronary artery, mammary artery or the ostium of a bi-pass vein. Duringthe diagnosis procedure, the physician advances and maneuvers thediagnostic catheter shaft within the artery, while at the same timeinjecting dye. The physician observes the dye using an angiographymonitor for visualization of the patient's coronary system.

[0009] The diagnostic catheter is advanced and maneuvered until thedistal end is properly engaged in the ostium of the coronary artery thephysician believes to contain the stenosis. Once seated in the ostium,the physician injects additional dye for observations of obstruction todye flow, indicative of the coronary disease.

[0010] For treatment of the coronary disease through angioplasty orother catheter based treatments, guide catheters are used. The guidecatheters provide access to the area within the arterial systemcontaining the stenotic lesion, and support for the treatment catheterwhich often includes a balloon dilatation system. Guide catheterssimilar in construction to diagnostic catheters, although they aregenerally larger in size. Prior art guide catheters typically have apre-shaped distal section or tip region to aid in access to the ostiumof the coronary artery to receive treatment.

[0011] In operation, the guide catheter is introduced over a guide wirethrough a previously placed femoral introducer sheath and advanced up tothe aortic arch. The guide wire can then be removed, and the guidecatheter can be advanced and maneuvered until the guide catheter softtip is properly engaged in the ostium of the coronary artery to bedilatated. A Y-adapter and manifold assembly are attached to the guidecatheter hub at the proximal end for implementation of therapeuticprocedures, such as dye delivery, flushing capabilities, pressuremonitoring and delivery of the dilatation balloon system.

[0012] Diagnostic catheters and guide catheters are manufactured inhundreds of shapes and curve styles to accommodate anatomical variancesin humans and to access specific areas within the coronary system. Curveshapes are also designed to provide support against the aortic wall whenseated within the ostium, to resist the tendency for a catheter to “popout” of the ostium (termed backout force) when injecting dye oradvancing a treatment catheter into the artery. Catheters are presentlyspecifically manufactured with high curve retention to maintain catheterplacement within the ostium and to resist backout forces.

[0013] During angioplasty procedures, the catheters must be able totraverse tortuous pathways through blood vessels to the stenosis in amanner as atraumatic as possible. Therefore, to limit insertion time anddiscomfort to the patient, the catheter must be stiff enough to resistthe formation of kinks, while at the same time the catheter must possessflexibility to be responsive to maneuvering forces when guiding thecatheter through the vascular system. It is important that the guidecatheter exhibit good torque control such that manipulation of aproximal portion of the guide catheter is responsively translated to thetip or distal end of the catheter to curve and guide the catheterthrough the tortuous pathways.

[0014] To meet the above performance requirements, guide catheters anddiagnostic catheters are manufactured using polymers in conjunction witha braid of high-strength fibers or stainless steel wires incorporatedinto the tube. The guide catheters are generally formed of three layers:a first inner layer commonly formed of polytetrafluoroethylene todecrease the coefficient of friction between a balloon catheter and theguide catheter; a middle layer consisting of braided wire for torquecontrol; and a third, outer layer commonly formed of polyethylene,polyurethane, polyether blocked amide (PEBA) or a nylon-blend for stablepositioning of the guide catheter, and providing backout support duringother treatment procedures.

[0015] During diagnostic and therapeutic procedures, it is oftennecessary to use more than one shaped or curved catheter to access theright coronary, left coronary, mammary artery, or bipass vein forvisualization of each vessel. The procedure of exchanging diagnosticcatheters for visualization of different vessels requires moreprocedural time and exposes the patient to extended x-ray time andfluoroscopy. Additionally, hospitals are required to inventory hundredsof catheters with various curves, tip shapes and diameters toaccommodate the various procedures for each patient.

[0016] It is desirable in catheter design for the inside diameter of thediagnostic or guide catheter to be maximized relative to the outsidediameter, providing maximum space for dye flow and dilatation catheterdelivery. While designing catheters to meet these design goals, thecatheters must continue to meet performance requirements of burstpressure requirements, kink resistance, curve retention, columnstrength, and torque control for advancement within the patient'svascular system.

SUMMARY OF THE INVENTION

[0017] The present invention relates to an improved guide or diagnosticcatheter having a simple braid-free catheter design, capable ofperforming the function of conventional diagnostic and guide catheters.

[0018] In a preferred embodiment, the catheter of the present inventionis for use as a guide or diagnostic catheter in catheter procedures. Thecatheter includes a generally elongate shaft formed of a singlepolymeric layer having a proximal end and a distal end. A lumen extendslongitudinally between the proximal end and the distal end. Means areincluded within the lumen of sufficient diameter for supporting theshaft during the catheter placement. The means for supporting the shaftmay include a core wire having a non-metallic coating. The means forsupporting the shaft may be curved, or alternatively, the shaft may becurved.

[0019] The means for supporting the shaft may alternately include asecond shaft for insertion into the lumen during the catheter procedure.The second shaft may include an elongate tubular member also having alumen extending longitudinally therethrough. The catheter assembly mayinclude means for securing the proximal end of the shaft to the proximalend of the second shaft. In an alternative embodiment, the means forsupporting the shaft is positioned over the shaft.

[0020] The present invention further includes a method of supporting aguide or diagnostic catheter for positioning the catheter within apatient's vascular system. An elongate shaft formed of a single layer ofpolymeric material is provided which is inserted within the patient'svascular system. An elongate tubular member formed of a polymericmaterial is advanced over the shaft, the shaft being of sufficientdiameter for transmitting forces between the tubular member and theshaft. A distal end of the tubular member is positioned within thepatient's vascular system. The shaft may include a core having apolymeric coating. The distal end of the shaft may be positioned withinthe ostium of the coronary to receive treatment.

[0021] Alternatively, the shaft may include a second tubular memberformed of a polymeric material. The proximal end of the second tubularmember may be locked to the proximal end of the shaft. The distal end ofthe second tubular member may be engaged in the ostium of a coronarywithin the vascular system.

[0022] Alternatively, the distal end of the first tubular member mayextend beyond the distal end of the second tubular member, and thedistal end of the first tubular member is engaged within the ostium of acoronary within the vascular system. The second tubular member isadvanced, tracking over the first tubular member until the distal end ofthe second tubular member is engaged in the ostium. The first tubularmember is removed from the patient's vascular system. Alternatively, thesecond tubular member may be removed from the patient's vascular system.

[0023] The present invention provides an economically feasiblediagnostic or guide catheter design which may be universally usable formost anatomical situations. The catheter of the present invention isless costly to manufacture than conventional catheters, while meetingperformance requirements for use, including kink-resistance, curveretention, column strength and torque control.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention will be further described with reference to theaccompanying drawings where like numbers refer to like parts in severalviews and wherein:

[0025]FIG. 1 is a perspective view of a catheter of the presentinvention having a tracking wire disposed therein.

[0026]FIG. 1A is a partial sectional view of the catheter of FIG. 1.

[0027]FIG. 1B is a sectional view of the catheter tracking wire of FIG.1.

[0028]FIG. 2 is a perspective view showing an alternative embodiment ofthe catheter of the present invention having an inner guide disposedtherein.

[0029]FIG. 2A is a partial sectional view showing the catheter of FIG.2.

[0030]FIG. 2B is a partial perspective view showing an alternativeembodiment of the catheter of FIG. 2.

[0031]FIG. 2C is a partial perspective view with a partial cutawayshowing an alternative embodiment of the catheter of FIG. 2.

[0032]FIG. 2D is a perspective view showing another alternativeembodiment of the catheter of the present invention having an outerguide.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] The present invention relates to an improved guide or diagnosticcatheter having a simple, braid-free design, which is capable ofperforming the functions of conventional diagnostic and guide catheters,while increasing lumen size back up support, radiopacity duringplacement, and dye control. The present invention provides aneconomically feasible diagnostic or guide catheter design which may beuniversally useable for most anatomical situations. The catheter of thepresent invention is less costly to manufacture than conventionalcatheters, while meeting performance requirements for use, includingkink resistance, curve retention, column strength and torque control.Although references throughout this specification may be specificallymade to either guide catheters or diagnostic catheters, references madeto one or the other are equally applicable to guide catheters anddiagnostic catheters, coronary, neuro, general peripheral, and anyvascular type catheters.

[0034] The focus of technology for guide and diagnostic catheters hascentered around designs which provide kink resistance and torqueresponse within a catheter tubular member. Kink resistance and torqueresponse are necessary so that manipulation of a proximal portion of thecatheter is responsively translated to the tip or distal end of thecatheter to curve and guide the catheter through the tortuous pathwaysof a patient's vascular system, to direct and position the distal tip ofthe catheter near the coronary area receiving treatment whilemaintaining an open lumen for the treatment procedure.

[0035] To achieve these performance characteristics, guide catheterdesigns have generally included a tubular member formed of three layers,which include braiding or coiling integral to the catheter tubeconstruction. The inner layer can be formed of a polytetrafluoroethyleneor lubricous polymer to decrease the coefficient of friction between theballoon catheter or other device and the guide catheter. The middlelayer consists of braided or helically wrapped wires or filaments, fortorque control. The outer layer is generally a polymeric layer whichgives the catheter stable positioning within the patient's vascularsystem by providing backup support during catheter procedures. The outerlayer is typically formed of a polyethylene, polyurethane, polyetherblocked amide or nylon-blend. Additionally, the outer layer usually isimpregnated with a radiopaque material, such as barium sulfate orbismuth subcarbonate, to allow for partial visualization of the cathetershaft during the catheter procedure.

[0036] Braided catheter designs are manufacturing intensive, requiringadditional costs, time, and manufacturing space. Additionally, braidedcatheter designs have performance limitations, including a larger wallthickness to accommodate the braided middle layer which limits availablelumen diameter for a given outside diameter.

[0037] The primary function of the braided middle layer, is to providesufficient torque and kink performance to the catheter body for properlypositioning the guide catheter within the coronary anatomy. Once thecatheter is positioned within the patient's vascular system, the needfor catheter kink and torque performance is no longer necessary.

[0038] The present invention provides a catheter (guide or diagnostic)which can be effectively positioned within the patient's coronaryanatomy, without utilizing a braided middle layer. The guide catheter ofthe present invention includes the use of a tracking wire which may bepositioned into the selected coronary artery and allows the guidecatheter to be tracked over the tracking wire into the same coronaryartery.

[0039]FIG. 1 shows a perspective view of the braidless guide catheterassembly 20 in accordance with the present invention. The catheterassembly 20 includes a guide catheter 22 positioned over a tracking wire24. The tracking wire 24 provides the guide catheter 22 with therequired performance torque response and kink resistance necessary forguiding the guide catheter 22 through the tortuous pathways of apatient's vascular system.

[0040] The guide catheter 22 includes a shaft 26 having a proximal end28 and a distal end 30. A lumen 32, shown in FIG. 1A, extendslongitudinally through the shaft from the proximal end 28 to the distalend 30. Operably connected to the proximal end 28 of the shaft 26 is ahub assembly 34, and connected to the distal end 30 of the shaft 26 is asoft tip 36.

[0041] The guide catheter 22 shaft 26 is formed of a single extrudedpolymer layer 38 with or without a lubricous inner coating 40. It isrecognized that shaft 26 may be formed by a co-extrusion process. In apreferred embodiment, layer 38 is formed of polyether blocked amide,polyethylene, polyurethane or a nylon blend. The layer 38 provides forstable positioning within a patient's vascular system and backup supportduring catheter procedures. Preferably, the layer 38 is impregnated witha radiopaque material, such as barium sulfate or bismuth subcarbonate,to allow for partial visualization of the shaft 26 during catheterprocedures.

[0042] The lubricous inner coating 40 allows for near frictionlessmovement of the tracking wire 24 within the guide catheter lumen 32. Ina preferred embodiment, the lubricous inner coating is a hydrophiliccoating. Alternatively, the guide catheter 22 may include an inner layerformed of a lubricous polymer, such as polytetrafluoroethylene.

[0043] The absence of a braided layer within the guide catheter 22allows the guide catheter 22 to have a larger inside diameter relativeto conventional guide catheters of a given outside diameter whichinclude the braided middle layer. By maximizing the inside diameterrelative to the outside diameter, the guide catheter 22 is able toprovide increased performance, including maximum dye flow and maximumcatheter delivery size.

[0044] The absence of the braided layer provides two alternative guidecatheter constructions. Preferably, the absence of the middle layerallows the catheter design to have an internal diameter larger than isavailable in conventional guide catheters, while continuing to providethe same amount of curve retention and backup support to the guidecatheter. In one embodiment, the internal diameter of the guide catheter22 is approximately 5 to 10 percent larger than the conventional braidedguide catheter having the same outside diameter with equivalent back-upand curve retention performance. In the second alternative, additionalpolymer may be added to the shaft 26 layer 38 to increase the catheterwall volume. The additional polymer provides additional backup supportto the guide catheter 22 during catheter treatment procedures.

[0045] Referring to FIG. 1B, a cross-sectional view of the tracking wire24 of FIG. 1 is generally shown. The tracking wire 24 includes anelongate shaft 42 having a proximal end 44 and a distal end 46. Locatedat the distal end 46 is a soft tip 48.

[0046] The shaft 42 includes an outer layer 50 formed over a core 52.The core 52 extends from the proximal end 44 to the distal end 46, butdoes not extend through the soft tip 48. In a preferred embodiment, thecore is wire, formed from stainless steel, a nickel titanium alloy (orNitinol), or other material which provides sufficient strength andsupport. The outer layer 50 is formed of polymer, preferably polyetherblocked amide, polyethylene, polyurethane or nylon blend. The outerlayer 50 can be impregnated with a radiopaque material, such as bariumsulfate or bismuth subcarbonate, for visualization of the shaft duringcatheter procedures.

[0047] In a preferred embodiment, the specialty wire 24 is formed bypositioning a polymer sleeve over a stainless steel wire. The wire andpolymer sleeve are pulled through a heated die, forming the polymersleeve over the stainless steel wire. The outer layer 50 is then coatedwith a lubricous substance to aid in movement of the specialty wire 24through the guide catheter 22 lumen 32. In a preferred embodiment, thelubricous outer coating is a hydrophilic coating. Alternatively, thespecialty wire 24 may be formed by other extrusion or co-extrusionprocesses as known in the art.

[0048] The tracking wire 24 soft tip 48 is formed of soft polymerextending beyond the core 52. The tip 48 may be of a uniform outsidediameter or preferably, the tip 48 is tapered for safer ostialengagement.

[0049] The guide catheter 22 is preferably straight, however the guidecatheter 12 may be curved and shaped for access to specific coronaryregions. With a straight guide catheter, the tracking wire 24 may becurved and shaped. With a curved tracking wire 24, the tracking wire 24is advanced within a patient's vascular system until the soft tip 48 isengaged in the ostium of the coronary artery to be treated. The guidecatheter 22 is then advanced over the specialty wire 24 until the guidecatheter soft tip 36 is similarly engaged in the ostium of the coronaryartery receiving treatment.

[0050] During an angioplasty procedure, the femoral artery is enteredpercutaneously and a sheath is inserted into the artery to provideaccess to the patient's vascular system. The tracking wire 24 isinserted into the femoral artery through the introducer sheath andadvanced up to and over the aortic arch. The tracking wire 24 isadvanced and torqued until the tip 36 is engaged in the ostium of thecoronary artery receiving treatment. Next, the guide catheter 22 isinserted into the femoral artery through the introducer sheath, over thetracking wire 24.

[0051] The guide catheter 22 tracks the tracking wire 24 duringadvancement through the patient's vascular system. The guide catheter 22is advanced over the tracking wire 24 until the distal end 30 passesover the aortic arch. As the guide catheter 22 is advanced over thetracking wire 24, through a patient's vascular system, the tracking wire24 provides the kink and torque performance of conventional braidedguide catheter designs.

[0052] With the soft tip 36 of the tracking wire 24 engaged in theostium of the coronary receiving treatment, the guide catheter isadvanced over the tracking wire until the guide catheter soft tip 36 issimilarly engaged in the ostium of the coronary receiving treatment.Once the guide catheter 22 is positioned within the ostium of thecoronary artery receiving treatment, the need for kink and torqueperformance is no longer necessary and the tracking wire 24 may beremoved.

[0053] Once the tracking wire 24 is removed, the guide catheter 22,including a larger lumen 32, is able to provide the physician withincreased dye delivery, and a larger lumen for accommodating a largerballoon dilatation catheter.

[0054] In a preferred embodiment, the tracking wire 24 has an outsidediameter of 0.038″ for use with 5F, 6F and 7F catheters and 0.063″ foruse with 8F, 9F and 10F catheters. It is also recognized that thetracking wire 24 may be used by the physician for guide catheterexchange procedures for exchanging to a larger guide catheter. Thetracking wire 24 would provide stability and support during removal andexchange of the guide catheter. Preferably, the tracking wire 24 wouldinclude a magnetically responsive/active section at its proximal end,which can be similar to the magnetic sections disclosed in the catheterexchange devices in application Ser. Nos. 08/048,492 and 07/929,083. Thetracking wire 24 would then be used for guide catheter exchangeprocedures, which can be similar to those disclosed in application Ser.No. ______ for use with magnetic exchange devices. Application Ser. Nos.07/929,083; 08/048,492; ______ and is herein incorporated by reference.

[0055] Referring to FIG. 2, another embodiment of the guide catheterassembly 20 of the present invention is generally shown. The catheterassembly 20 includes a guide catheter 22 and an inner guide member 60.The construction of the guide catheter 22 can be similar to theconstruction of the guide catheter 22 shown and described previously inFIG. 1. The catheter assembly 20 with the inner guide 60 provides thephysician with a guide catheter that has a simple, braid-free catheterdesign, which is capable of performing the functions of conventionalguide catheters.

[0056] Referring to FIGS. 2, 2A and 2B, the inner guide 60 generallyincludes a shaft 62 having a proximal end 64 and a distal end 66. Alumen 68 extends longitudinally through the shaft 62 from the proximalend 64 to the distal end 66. Operably connected to the proximal end 64of the shaft 62 is a hub assembly 70, for connection to catheterizationequipment, including the hub assembly 34 of guide catheter 22. Connectedto the distal end 66 of the shaft 62 is a soft tip 72, which may betapered.

[0057] The inner guide 60 is formed using extrusion processes which canbe similar to the formation of the guide catheter 22. In a preferredembodiment, the inner guide 60 includes a single layer 74 formed ofextruded polymer, preferably fiber filled with liquid crystal polymer(LCP), glass fiber, Kevlar fiber, carbon fiber, or other similar fiber.Alternatively, the inner guide 60 may be multilayered.

[0058] The single layer 74 is formed of a polymeric material, such aspolyether blocked amide, polyethylene, polyurethane, or a nylon blend,for stable positioning, kink-resistance, and torque control of the guidecatheter 22.

[0059] Due to the relatively thin walls of guide catheter 22 and innerguide 60, the inner guide 60 may also be impregnated with radiopaquematerials such as barium sulfate, or bismuth subcarbonate forvisualization of the shaft during catheterization procedures. In thepreferred embodiment, the inner guide 60 single layer 74 is formed of apolyether blocked amide or PEBA impregnated with 20-60 percentradiopaque materials having a relatively high durometer.

[0060] The outside diameter of the inner guide 60 is sized for slidableinsertion within the lumen of the guide catheter 22. The outsidediameter of the inner guide 60 is of sufficient size to provide support,torqueability, and kink-resistance to guide catheter 22 for positioningguide catheter 27 within the patient's coronary anatomy. The insidediameter of the inner guide 60 lumen 68 is sized to accommodate standardcatheter procedure guide wires. In the preferred embodiment, the insidediameter of inner guide 60 lumen 68 is between 0.038 and 0.040 inches toaccommodate 0.035 inch guide wires.

[0061] When the inner guide 60 is inserted within the guide catheter 22lumen 32, the inner guide hub assembly 70 connects to the guide catheter22 hub assembly 34. By locking the inner guide 60 hub assembly 70 to theguide catheter 22 hub assembly 34, the inner guide 60 may be used toposition and torque the guide catheter 22 into the desired location inthe coronary anatomy. The inner guide 60 provides support,kink-resistance, and torquability to the braidless guide catheter 22during introduction and positioning of the guide catheter within thepatient's vascular system. The inner guide 60 may or may not extendbeyond the distal end 30 of guide catheter 22.

[0062] With the inner guide 60 hub assembly 70 locked to the guidecatheter 22 hub assembly 34, dye may be injected into the patient'svascular system through the inner guide 60 lumen 68. By injecting dyethrough the inner guide lumen 68, the amount of dye released into thepatient's system may be easily controlled, especially where the innerguide 60 is positioned within a larger size catheter. In the preferredembodiment, the outside diameter of the inner guide 60 varies relativeto the size of guide catheter 22, but the inside diameter of inner guideis constant, preferably approximately 0.038 inches. A Y-adaptor andmanifold assembly may be attached to the catheter assembly 20 includingthe guide catheter 22 and inner guide 60 for contrast dye and flushdelivery and pressure monitoring. Additionally, by locking the innerguide hub assembly 70 with the catheter hub assembly 34, the catheterassembly 20 acts as an anti-bleeding device for preventing back bleedingthrough the guide catheter 22.

[0063] In use, the femoral artery is entered percutaneously and a sheathis inserted into the artery to provide access for the catheter assembly20 to the patient's vascular system. The guide wire, preferably a 0.035inch wire, is inserted through the femoral sheath into the patient'svascular system and advanced up and over the aortic arch. The innerguide 60 is inserted into the guide catheter 22, with hub assembly 70locked to hub assembly 34, to form catheter assembly 20. The catheterassembly 20 is introduced over the guide wire through the femoralintroducer sheath and advanced up to the aortic arch. As the catheterassembly 20 is advanced up and over the aortic arch, the inner guide 60provides support, kink-resistance, and torquability to the braidlessguide catheter 22.

[0064] After advancing the catheter assembly 20 over the aortic arch,the guide wire can then be removed. A Y-adaptor and manifold assemblyare attached to the catheter assembly 20 for injection of dye contrast,flush delivery, and pressure monitoring. The contrast media allows thephysician to locate the ostium for seating the guide catheter 22.

[0065] The catheter assembly 20 is now advanced and torqued until it isengaged in the ostium of the vessel which is to receive treatment. Oncethe guide catheter 22 is engaged within the desired ostium, the innerguide 60 may be removed. The luer attached to the inner guide hubassembly 70 and the catheter hub assembly 34 is unlocked, and the innerguide hub assembly 70 is disconnected from the catheter hub assembly 34.The inner guide 60 is pulled out and removed.

[0066] The inner guide 60 provides torquability and kink-resistance tothe guide catheter 22 for positioning the guide catheter 22 within thepatient's coronary anatomy. Once the guide catheter 22 is correctlypositioned within the patient's coronary system, the need forkink-resistance and torquability is no longer necessary, and the innerguide 60 may be removed. After removal of the inner guide 60, thephysician may proceed with treatment of the diseased area, such asthrough the use of a balloon dilatation system, as the physician wouldwhen using a conventional guide catheter.

[0067] In a preferred embodiment, the inner guide 60 may be curved orshaped, and guide catheter 22 straight. The curved inner guide 60 wouldgive shape to the catheter assembly 20 for accessing specific areaswithin the patient's coronary anatomy. Alternatively, it is recognizedthat the same function may be accomplished by providing a straight innerguide 60 with a curved or shaped guide catheter 22.

[0068] In one preferred embodiment for smaller catheter sizes, such as5F, 6F, or 7F, the inner guide 60 is curved or shaped, and the guidecatheter 22 is curveless or straight. Referring to FIG. 2B, the innerguide 60 distal end 66 extends beyond the guide catheter 22 distal end30. With the catheter assembly 20 advanced over the aortic arch, theinner guide 60 distal end 66 (and specifically tip 72) is engaged in theostium of the vessel to receive treatment. The guide catheter 22 istracked over the inner guide 60 until the distal end 30 is similarlyengaged in the ostium to receive treatment.

[0069] The inner guide, which is curved or shaped, is then removed. Thecurveless guide catheter 22 is positioned within the ostium of thecoronary artery receiving treatment. The curveless guide catheter 22provides better support to the treatment system while being lesstraumatic to the patient's vascular system than a shaped cathetersystem, which would induce preformed stresses within the vessels due toits curved structure.

[0070] In another preferred embodiment for larger catheter sizes, suchas 8F, 9F and 10F, the inner guide 60 is curveless and the guidecatheter 22 is curved or shaped. Referring to FIG. 2C, the guidecatheter 22 distal end 30 extends beyond the inner guide 60 distal end66. The inner guide 60 provides torqueability and kink resistance toguide catheter 22 for positioning the guide catheter 22 within thepatient's coronary anatomy. Once the catheter assembly 20 is advancedover the aortic arch, the catheter assembly 20 is torqued and advanceduntil the guide catheter 22 distal end 30 is engaged in the ostium ofthe vessel to receive treatment.

[0071] Once the guide catheter 22 is correctly positioned within thepatient's coronary system, the need for kink resistance andtorqueability is no longer necessary, and the inner guide 60 may beremoved. After removal of the inner guide 60, the physician may proceedwith treatment of the diseased area, such as through the use of aballoon dilatation system, as the physician would when using aconventional guide catheter.

[0072] Referring to FIG. 2D, yet another embodiment of the presentinvention is shown. The catheter assembly 20 includes a guide catheter22 and an outer guide 80. The outer guide 80 can be similar inconstruction to the inner guide 60 which was previously detailed herein.Similarly, the outer guide 80 provides the same function as previouslydescribed inner guide 60, in that it provides torqueability and kinkresistance to the guide catheter 22 for positioning the guide catheter22 within the patient's coronary anatomy. Once the guide catheter 22 iscorrectly positioned within the patient's coronary system, the need forkink resistance and torqueability is no longer necessary, and the outerguide 80 may be removed. After removal of the outer guide 80, thephysician may proceed with treatment of the diseased area, such asthrough the use of a balloon dilatation system, as the physician wouldwhen using a conventional guide catheter.

[0073] The outer guide 80 may be curved or shaped, and the guidecatheter 22 curveless or straight. The curved outer guide 80 would giveshape to the catheter assembly 20 for accessing specific areas withinthe patient's coronary anatomy. Alternatively, it is recognized thatsimilar functions may be accomplished by providing a straight orcurveless outer guide 80 with a curved or shaped guide catheter 22. Theguide catheter 22 may or may not extend beyond a distal end 82 of theouter guide 80. In use, the outer guide 80 functions similar to innerguide 60 during catheterization procedures. The femoral artery isentered percutaneously, and a sheath is inserted into the artery toprovide access for the catheter assembly 20 to the patient's vascularsystem. A guide wire is inserted through the femoral sheath into thepatient's vascular system and advanced up over the aortic arch. Theouter guide 80 is positioned over the guide catheter 22 to form catheterassembly 20. The outer guide 80 and guide catheter 22 may be securedtogether at their proximal ends using a hub assembly similar to thatpreviously described herein, or they may be secured together by othermeans, such as the use of magnetically active segments which can besimilar to those disclosed in U.S. application Ser. Nos. 07/929,083;08/048,429; and ______ for use with magnetic devices. U.S. applicationSer. Nos. 07/929,083; 08/048,429; and ______ has been previouslyincorporated into this application by reference.

[0074] The catheter assembly 20 is introduced over the guide wirethrough the femoral introducer sheath and advanced up to and over theaortic arch. As the catheter assembly 20 is advanced up and over theaortic arch, the outer guide 80 provides support, kink resistance, andtorqueability to the braidless guide catheter 22.

[0075] After advancing the catheter assembly 20 over the aortic arch,the guide wire can be removed. A Y-adapter and manifold assembly may beattached to the catheter assembly 20 for injection of die contrast,flush delivery, and pressure monitoring. The contrast media allows thephysician to locate the ostium for seating the guide catheter 22.

[0076] The catheter assembly 20 is now advanced and torqued until it isengaged in the ostium of the vessel which is to receive treatment. Theguide catheter 22 distal end 36 may be engaged in the ostium.Alternatively, if the outer guide 80 extends beyond the guide catheter22, the outer guide 80 distal end 82 may be engaged within the coronaryostium, and then the guide catheter 22 distal end 30 may be advanced andsimilarly engaged in the ostium of the coronary to receive treatment.Once the guide catheter 22 is correctly positioned within the patient'scoronary system, the need for kink resistance and torqueability is nolonger necessary, and the outer guide 80 may be removed. After removalof the outer guide 80, the physician may proceed with treatment of thediseased area, such as through the use of a balloon dilatation system,as the physician when using a conventional guide catheter.

[0077] The guide catheter assembly 20 of the present invention, wouldprovide for increased performance during diagnostic procedures. Thedimensions of the diagnostic catheter could be scaled appropriately andconstructed to withstand adequate burst pressures for high pressure dyedelivery typical of diagnostic procedures. The present invention wouldallow the physician to use diagnostic catheter shapes for visualizingvarious areas of the coronary system, without having to remove thediagnostic catheter from the patient's body. The time saving procedureusing the present invention also results in less patient exposure tofluoroscopy.

[0078] The present invention provides a catheter which can beeffectively positioned within the patient's coronary anatomy, withoututilizing a braided middle layer. The absence of a braided layer withinthe guide catheter allows the guide catheter to have a lumen with alarger inside diameter relative to conventional guide catheters of agiven outside diameter formed of braided construction. By maximizing theinside diameter relative to the outside, the guide catheter is able toprovide increased performance, including maximum dye flow and maximumcatheter delivery size. Additionally, the guide catheter of the presentinvention provides equivalent back-up and curve retention performance tothat of conventional guide catheters.

[0079] It will be understood, that this disclosure is, in many respects,only illustrative. Changes may be made in details, particularly inmatters of shape, size, material, and arrangement of parts withoutexceeding the scope of the invention. Accordingly, the scope of theinvention is as defined within the language of the appended claims.

What is claimed is:
 1. A catheter assembly for use as a guide ordiagnostic catheter in catheter procedures comprising: a generallyelongate shaft formed of a polymeric layer having a proximal end and adistal end, with a lumen extending longitudinally between the proximalend and the distal end; and means insertable within the lumen ofsufficient diameter for supporting the shaft during catheter placement.2. The catheter assembly of claim 1 , wherein the means for supportingthe shaft includes: a support member having a core wire and anonmetallic coating thereon.
 3. The catheter assembly of claim 2 ,wherein the support member is generally elongate having a proximal endand a distal end with a soft tip located at the distal end.
 4. Thecatheter assembly of claim 3 , wherein the support member distal end istapered.
 5. The catheter assembly of claim 1 , wherein the means forsupporting the shaft is curved.
 6. The catheter assembly of claim 1 ,wherein the shaft is curved.
 7. The catheter assembly of claim 1 ,wherein the means for supporting the shaft comprises: a second shafthaving an outside diameter less than the diameter of the lumen forinsertion into the lumen during the catheter placement.
 8. The catheterassembly of claim 7 , wherein the second shaft is an elongate tubularmember.
 9. The catheter assembly of claim 7 , further including meansfor securing the proximal end of the shaft to a proximal end of thesecond shaft.
 10. A catheter assembly for use as a guide or diagnosticcatheter in catheter procedures comprising: a generally elongate shaftformed of a polymeric layer having a proximal end and a distal end, witha lumen extending longitudinally between the proximal end and thedistal; and means positioned over the shaft having a lumen of sufficientinside diameter for supporting the shaft during catheter placement. 11.The catheter assembly of claim 10 , further including: means forsecuring the proximal end of the shaft to a proximal end of the meansfor supporting the shaft during catheter placement.
 12. A method ofsupporting a guide or diagnostic catheter for positioning the catheterwithin a patients vascular system, the method comprising: providing anelongate shaft including a core having a nonmetallic coating; insertingthe shaft within the patient's vascular system; advancing an elongatetubular member formed of a polymeric material over the shaft, the shaftbeing of sufficient diameter for transmitting forces between the tubularmember and the shaft; positioning a distal end of the tubular memberwithin the patient's vascular system.
 11. The method of claim 10 ,further comprising the step of: positioning a distal end of the shaftwithin an ostium of the patient's vascular system.
 12. The method ofclaim 11 , further comprising the step of: advancing the tubular memberover the shaft until a distal end of the tubular member is positionedwithin the ostium.
 13. The method of claim 10 , further comprising thestep of: removing the shaft.
 14. A method of supporting a guide ordiagnostic catheter for positioning the catheter within a patient'svascular system, the method comprising: providing a first elongatetubular member; inserting the first elongate tubular member within asecond elongate tubular member to form a catheter assembly fortransmitting forces between the first tubular member and second tubularmember within the catheter assembly; inserting the catheter assemblywithin a patient's vascular system; and positioning a distal end of thecatheter assembly within the patient's vascular system.
 15. The methodof claim 14 , further including the step of: locking a proximal end ofthe first tubular member to the proximal end of the second tubularmember.
 16. The method of claim 14 , further including the step of:engaging a distal end of the second tubular member in an ostium of acoronary within the vascular system.
 17. The method of claim 14 ,wherein a distal end of the first tubular member extends beyond a distalend of the second tubular member, further comprising the steps of:engaging the distal end of the first tubular member within an ostium ofa coronary within the vascular system.
 18. The method of claim 17 ,further comprising the steps of: tracking the second tubular member overthe first tubular member until the distal end of the second tubularmember is engaged in the ostium; and removing the first tubular memberfrom the patient's vascular system.
 19. The method of claim 14 , wherein the second tubular member is formed of a polymeric material.
 20. Themethod of claim 14 , further including: removing the second tubularmember from the patient's vascular system.
 21. The method of claim 14 ,wherein the first tubular member is formed of a polymeric material.